Improvement in balanced and cut-off valves



.l. W. THOMPSON. l Ba'lancgdnd lCut-off Val-ve. Y

`Na 162,714. i Y PatentedApri|27,'1875.

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JOSEPH W. THOMPSON, OF SALEM, OHIO, ASSIGNOR YTO HIMSELF AND BUCKEYE ENGINE COMPANY, OF SAME PLACE.

IMPROVEMENT IN BALANCED AND CUT-OFF VLVES.

Specification fcrmingpart of Letters Patent No. 162,714, dated April 27, 1875 application filed October 10, 1874.

To all whom it may concern Be it known that I, JOSEPH W. THOMPSON, of Salem, in the county of Columbiana and State of Ohio, have invented a new and Improved Balanced and Automatic Gut-Off Valve, of which the following is a specification:

The first part of the invention consists of the valve, so contrived that steam is admitted to a chamber in the main valve containing the cut-ott', and it exhausts into the ordinary steamchest at the ends of the valve.

The top of the chamber or back of the valve works in close proximity to the steamchest cover, and is furnished with one or more openings, to whichrare iitted suitably-constructed packing-rings, which work, steamtight, against the cover, and, by embracing or surrounding the openings which communicate with the steam-pipe, admit steam to the chamber of the valve. The area of said opening or openings is made just sufficient to hold the valve to its seat, thus serving to balance it.

The essential advantage of this arrangement is that the space ordinarily required in the shell of the cylinder, between the bore and the valve-face, for the exhaust-passages is avoided, and the main Valve-face is brought as near to the bore as is consistent with the necessary strength of material in the valve, also, the exhaust having` a more direct passage to the pipe after leaving the cylinder,

y there is less back pressure than with the or- Figure l is a horizontal section of the valve and valve-chest arranged upon the side of the engine to work on a vertical valve-face. Fig. 2 is a longitudinal sectional elevation taken on the line cc x of Fig. l. Fig. 3 is an inside elevation of the top of the steam-chest.

Similar letters of reference indicate corresponding parts.

Ais the main valve, in which is a chamber, B, inclosed by the cover C, which has an opening, D, to admit the steam to the chamber for entering the ports E ot' the engine through the passages F in the valve. The opening D is also for balancing the valve by means of a packing-ring or piston, Gr, together with suitable steam-packing arranged in said opening to work against the faceplate H of the cover I of the steam-chest. J is a spring, used to keep the piston on the face-plate when the steam is shut oft. There may be two or more of these openings D in the cover of the steam-chamber B, if necessary. The steam enters the chamber through the pipe K, and it exhausts at the ends of the valve, through the steam-chest L, into passagesM in the steam-chest cover leading to the exhaust-pipe N. O is the cut-o valve, which is arranged in chamber C on the back of valve A. The stem P of this valve extends out of the steam-chest through the hollow tube Q, forming part of the main valvestem, and it connects with its rock-arm R in the line of the connection ot' the main valvestem With its rock-arm S, and this rock-arm is pivoted on the rock-arm S at its middle or thereabout.

The eccentric-rod T of the cut-off valve is connected to the rock-arm R in the line of the pivot of the rock-arm of the main valve, and the eccentric for working it is iitted on the crank-shaft, so that it can be shifted around it for cutting oil sooner or later, according to the speed of the engine.

I reserve the right to make future application for Letters Patent on the rack-arm or valve-gear S.

Having thus described my invention, I 12. The combination of the tubular valveclairn as new and desire to secure by Lett-ers rod Q with the rod.l P, the valves A O, lheir Patent eccentrics, and-connectingrods, as' herein 1. The combination of the sliding hollow. shown and described. Y steam-valve A, and inclosed sliding cut-'off valve with the steam-chest; L, having steam- JOSEPH W' THOMPSON induction pipe K, exhaust-passages M M, and Witnesses :y pipe N, all constructed and relatively arranged p C. VSEDGrWICK, substantially as herein shown and described. T. B. MOSHER. 

